Brake slack adjuster



2 Sheets-Sheet 1 Filed Feb. 15, 1951 in, du 1 Nov. 16, 1954 e. B. DOREY 2,694,471

BRAKE SLACK ADJUSTER Filed Feb. 13, 1951 2 Sheets-Sheet 2 United States Patent 2.694. 7 BRAKE SLAK ADJUSTER George B. Dorey, Westmount, Quebec, Canada, assignor to Continental'Transport Appliances, Limited, Montreal, Quebec, Canada, a corporation of Canada Application February 13, 1951, Serial No. 210,748

scans, to. 821-202) The invention relates to an improved type of brake slack adjuster for railway cars and the like, and has for its object the attainment of a high degree of precision in the operation of the device to ensure uniform functioning of adjustment under all conditions of operations.

A specific object of the invention is to provide a pivotally mounted lever disposed to extend from a fixed pivot ,on the car structure to the push'rod and which acts as a radial'arm to support and guide slack adjuster spring operating mechanism thereby restricting the movement of the spring mechanism to a given path irrespective of the position of the floating levers and rods. The unprovement is particularly adapted for employment in connection with a slack adjuster carried by the floating center rod structure of a brake leverage system wherein considerable lateral movement takes place under different positions of the levers and rods and it is a purpose of my improvement to restrict the movement of the spring mechanism to a path of movement substantially parallel to the path of movement of the push rod while still permitting a connection with the center rod allowing free lateral movement of the center rod structure.

For further comprehension of my invention reference may be had to the accompanying drawings wherein:

'Fig. 1 is a plan view ofa portion of the car framing with my improvements applied thereto, said view showing the brake in released position.

Fig. 2 is a vertical side elevational view of the structpre shown in Fig. l as viewed on a line of said Fig. 3 is a plan view similar to Fig. 1 except that the brake is shown with the push rod moved forwardly to the position where adjustment of travel becomes efiective.

Fig. 4 is a vertical sectional view on an enlarged scale ta en rou h he Sp m chanism on a line 47.4 o

Fig. 5 is a vertical sectional view on an enlarged scale taken through the'center rod structure as seen on a line 5-5 of Fig. 3.

In said drawings the improvement is shown as applied to a railway car of conventional design and in,- cluding the usual center sills -10 carrying a bracket 11 to which is bolted or otherwise secured the brake cylinder 12. Associated with the brake cylinder is a hollow push rod cylinder 13 within which is loosely mounted a push rod 14 having a stem 15 extending within push rod cylinder 13' and said rod at its outer end is formed with a pair of jaws 1 6,1,6. The rod 13 is longitudinally movable in a forward direction in unison wtih the push rod cylinder 13 upon the admission of compressed air in the cylinder 12 through the inlet pipe 17. Sandwiched between the pair of jaws 1 6.16 is one of the brake levers 18 which is ivotally connected to the push rod by a pivot 19.

'Leading from the outer end of the push rod is a hand brake chain connection 20 which is connected therewith by means of a clevis 21 which straddles the push rod jaws 1d and also receives the pivot 19. i

Pivotally connected to the end of the lever 18 which i e t ro t pu h rod s. a top red 22 which leads tn one of the trucks (not shown) and intermediate its ends said lever 18 is connected to a center tie rod structure 23 which at its opposite ends makes connection with the brake arrangement leading to the brake shoes at the opposite end of car (not shown), The center tie rod structure is divided lengthwise into two sections indicated at 24 and 25 respectively and the ends are screw threaded to present right and left hand screw threads as indicated and 2 respectively and said threaded ends are ice connected by a complementary screw threaded turnbuckle 28 having a ratchet wheel 29 fixedly associated therewith.

Extending from each end of the turnbuckle 28 are tubular extensions 30 each having a collar 31 at its outer end. Mounted on the collar 31 adjacent the lever 18 is a bell crank lever arrangement 32 mounted for universal movement and having angularly related arms 33 and 34, the arm 33 extending laterally outwardly across the plane of the push rod and the arm 34 being pivotally mounted on said arm 33 for up and down movement whereby ratcheting engagement with the ratchet is effected upon horizontal swinging movement of the arm 33.

Underlying the arm 33 of the bell crank lever is a link member 35 which is pivotally mounted at 36 on a bracket 37 which in turn is rigidly secured to the center sill 10. Said member 35 is extended towards the push rod to intersect and underlie the arm 33 and at its outer end engages with a push rod head 38,

The push rod head 38 includes a vertically extending projection 39 and a platform extension 40 which is welded to the clevis 21 and thereby supported at one end and said platform is further supported on the push rod stem 15 by a downwardly extending pedestal plate which encircles the stem of the push rod and is welded at its upper end to the projection 39. The platform supports the end of the link member 35 and in' order to provide for free sliding'movement of the link on the platform the platform plate is recessed at .4041 to accommodate the head of pivot 19.

The outer end of the link member 35 is of arcuate shape as indicated at 41 to engage with the projection 39 of the push rod head.

lnterposed between the link member 35 and bracket 42 rigidly mounted on the car is spring mechanism 43. Said mechanism is pivotally mounted at one end at 44 to the link member 35 at a location intermediate the pivot 36 and the push rod, and at its opposite end is pivotally mounted to the bracket .42 at 45.

The spring mechanism includes telescopically related members formed of inner and outer shouldered members as indicated at 46 and 47 respectively and an interposed spring 48 encircling the inner member.

The outer member 47 is in the form of a hollow box shaped housing including top,b ottom and side walls as indicated at .49, 5.0 and 51 respectively and the side walls are extended downwardly below the level of the bottom wall 50 to present a pair of hinging lugs 52.. 52 between which a locking pawl 53 is disposed and pivotally mounted on said walls on pivot 54.

The pawl 53 includes an upper detent portion 55 and.

a lower weighted section 56 in order to bias the pawl to a substantially vertical position.

The inner member 46'includes a pair of rails 5757 maintained in spaced relation at each end by filler members welded in place, one of said fillers being in the form of a screw threaded rod 58 and at the opposite end by a tiottlhed block 59 having a series of ratchet teeth 60 an Engaging with the screw threaded end of the rod 58 is a clevis 62 having a pair of jaws 636 3 through which the pivot 44 extends.

The arm 33 of the bell crank lever 32 is slotted at 64 to receive the pivot pin .44 and thus cause the bell crank lever arm 33 and the link member 35 to move in unison, the swing of the link member restricting the movement of the spring mechanism to a given path and the slotted connection 64 permitting lateral movement of the floating leverage system.

The operation of the device is as follows: Assuming the brake in released position as in Fig. 1, the push rod moves forwardly taking along the link member 35 and swinging the bell crank lever and by reason of the pivotal conection 44 compressing the spring. During the compression movement of the spring the detent portion 55 of the pawl successively engages with the ratchet teeth 60 and 61 thereby retaining the spring under compression and permitting the return of the piston and brake levers to release position. Should the travel of the piston exceed a predetermined extent of travel the spring 48 is compressed sufficiently for the tooth 61 to override the pawl detent 55 and the weighted section 56 then assumes a vertical position as shown in Fig. 4. With the pawl in vertical overbalanced position as shown in Fig. 4, the spring mechanism is free to return to released position taking along the arm 33 of the bell crank lever assembly and thereby rotating the turn buckle in a screw take up direction by reason of the interengagement between pawl arm 33 and the teeth of the ratchet wheel.

While the improved linkage system of controlling the movement of the spring mechanism to a given path is of parti ular importance in connection with the operation of a slack adjuster mounted on the floating parts of the leverage system it will be appreciated that the improvement is applicable wherever a slack adjuster is operated by spring pressure.

I claim:

1. In a railway car brake system, in combination with the car structure and a cylinder mounted on the said structure having a movable push rod operable thereby for applying the brake and a slack adjuster having a take up device operable by rotation for taking up slack in the brake system; means for rotating the take up device including co-operating ratchet and lever mechanism mounted on said take up device, said lever mechanism including an operating arm pivotally mounted on the take up device having swinging movement for operating the take up device; a radius bar pivoted adjacent one end on the car structure at a location spaced appreciably outwardly from the push rod and having the opposite end formed of arcuate shape; an abutment on the push rod co-acting with the arcuate shaped end of the radius bar for moving the latter upon movement of the push rod in a brake applying direction; a connection between the radius bar and the operating arm of the take up device whereby said bar and lever move in unison upon movement of the push rod in a brake applying direction; a bracket on the car structure spaced lengthwise from the radius bar; and spring mechanism interposed between the said bracket and radius bar for operating the take up device by movement of the radius bar, said spring being tensioned upon movement of the push rod in a brake applying direction and upon release of the spring tension operating to move the radius bar and operating arm in a take up direction.

2. In a railway car brake system, in combination with the car structure and a brake cylinder mounted on the said car structure having a movable push rod operable by the cylinder for applying the brake, said brake system including a slack adjuster operable by spring pressure for automatically taking up slack in the brake system and limiting piston travel within a predetermined limit, said slack adjuster including a take up device operable by rotation to take up slack; means for rotating the take up device including a ratchet wheel on the take up device and a bell crank lever pivotally mounted on the take up device having one arm co-acting with the ratchet wheel and having another arm constituting the operating arm extending laterally from the take up device and having swinging movement for operating the latter; a radius bar pivoted to the car structure at one side of the push rod and extended towards the said push rod and movable with the latter in a brake applying direction; a connection between the radius bar and the operating arm of the adjuster whereby said respective members move in unison; a bracket on the car structure spaced lengthwise from the radius bar; and spring mechanism interposed between the radius bar and bracket for operating the adjuster, said spring mechanism being tensioned upon movement of the push rod in the-brake applying direction; retaining means co-operating with said spring mechanism for holding the same under tension until the predetermined extent of piston travel is obtained, said retaining means including interengaging pawl and ratchet mechanism, said pawl and ratchet being arranged to disengage upon movement of the push rod beyond the predetermined limit and release the spring tension for operating the slack adjuster.

3. In a railway car brake system, in combination with the car structure and a cylinder mounted on the said structure having a movable push rod operable thereby for applying the brake and an automatically operable slack adjuster device including a take up device operable by rotation for taking up slack in the brake system; means for rotatlng the take up device including a ratchet wheel on the take up device and alever having an, oo-

operating with the ratchet wheel pivoted on the take up device and another arm constituting an operating arm extending from the pivot and having swinging movement for operating the take up device, said operating arm being formed with an elongated slot; and a radius bar pivoted at one end to the car structure at one side of the push rod and extended towards the said push rod to move in unison therewith upon movement of the push rod in a brake applying direction; a pivot extending through the radius bar and slot of the operating arm; a bracket on the car structure spaced from the pivot; and spring mechanism interposed between said pivot and the bracket, said spring mechanism including oppositely disposed shouldered members pivoted to the radius bar and bracket respectively and having a spring interposed between said shoulders of the respective shouldered members and compressible upon relative approach of the shouldered members, said spring upon release of the spring compression acting to move the operating arm of the take up device and take up slack in the brake system.

4. In a railway car brake leverage system including interconnected levers, in combination with the car structure and a cylinder mounted on said structure having a movable push rod connected to one of the levers, said rod being movable in a forward direction to apply the brake, and an automatically operable slack adjuster having a take up device operable by rotation for varying the relation between the push rod and levers and take up slack in the brake system; means for rotating the take up device including ratchet wheel and lever mechanism carried by the take up device, said lever mechanism including a bell crank lever having an arm cooperating with the ratchet wheel and another arm extending laterally from the take up device for swinging movement and constituting the operating arm of the take up device, said last named arm being operable in one direction by movement of the push rod in the brake applying direction, said arm being formed with an elongated slot; a radius bar pivoted at one end to the car structure and extended towards the push rod; an abutment on the push rod co-acting with the radius bar to move the latter upon movement of the push rod in the brake applying direction; a pivot extending through the radius bar and slot of the operating arm for causing the radius bar and arm to swing in unison; a bracket on the car structure spaced from the said pivot; and spring mechanism interposed between the bracket and radius bar, said spring mechanism being tensioned on forward movement of the push rod and on release of said tension operating to swing the radius bar and operating arm-of the take up device in a take up direction.

5. In a railway car brake leverage system including interconnected levers, in combination with the car structure and a cylinder mounted on the said structure having a movable push rod connected to one of the levers, said push rod being movable in a forward direction to apply the brake, and said system including an automatically operable slack adjuster having a take up device operable by rotation for varying the relation between the push rod and levers and take up slack in the brake system; means for rotating the take up device including a ratchet Wheel on the take up device and a bell crank lever pivoted on the take up device and including an arm co-operating with the ratchet wheel and another arm extending laterally from the take up device and constituting an operating arm; means for moving the operating arm of the take up device including a radius bar connected to the operating arm and pivoted on the car structure at one side of the push rod and extended towards the latter; an abutment on the push rod engaging the extended end of the radius bar whereby the said bar is moved in unison with the push rod on forward movement of the latter in a brake applying direction; and a spring for operating the take up device connected to the radius bar and tensioned on forward movement of the radius bar whereby upon release of the spring tension said radius bar is moved to operate the take up device.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 795,401 Leigh July 25, 1905 1,559,143 Anderson Oct. 27, 1925 

